This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. MN-221 is an investigational new drug that is being tested for the treatment of severe asthma exacerbation. The purpose of this research study is to evaluate the effectiveness and safety of MN-221 compared to placebo in subjects with severe asthma exacerbation as an adjunct to standardized theraphy.